Strip rubber and method and apparatus for producing the same



June 2, 1936. c w LEGUlLLON 2,042,536

STRIP RUBBER AND METHOD AND APPARATUS FOR PRODUCING THE SAME Filed Oct. 12, 1933 2 Sheets-Shet 1 |liillllllllllllllllllllllllllllllllllllllllllllllllllil vm/ mmflm l W mm? [haw/E5 ZZ/fLEgLIi/[UI'Y Zig- June 2, 1936. c. w. LEGUILLON 2,042,536

STRIP RUBBER AND METHOD AND APPARATUS FOR PRODUCING THE SAME Filed on. 12 1933 2 Sheets-Sheet 2.

Patented June 2, 1936 UNITED STATES PATENT OFFICE STRIP RUBBER RATUS FOR AND METHOD AND APPA- PRODUCING THE SAME Charles W. Leguillon, ,Akron,

The B. F. Goodrich Company,

Ohio, assignor to New York, N. Y.,

24 Claims.

This invention relates to the manufacture ofv strip rubber such for exampleas the elastic thread used in elastic garments.

The chief objects of the invention are to provide. an improved elastic thread, and to provide procedure and apparatus for making the thread conveniently, economically and of uniformly high quality.

These and further objects will be apparentfrom the following description, reference being had to the accompanying drawings in which:

Fig. 1 is an elevation, with parts broken away and in section, of apparatus embodying the invention and used in the practice thereof in its preferred form.

Fig. 2 is a section taken along the line 2-2 of Fig. 1.

Fig. 3 is an enlarged cross section of the rubber covered Wire at the squeeze-cutting position.

Fig. 4 is an enlarged perspective View of a thread made in accordance with and embodying the invention in. its. preferred form.

Figs. 5, 6, '7, and 8 are side elevations, with parts broken away and in section, of portions of a modified form of the apparatus for carrying out a modified form of the procedure.

Figs. 9 and 10 are sections showing a modified form of a squeeze-cutting apparatus, Fig. 9 being taken along the line 9-9 of Fig. 10, and Fig. 10 being taken along the line l-I ll of Fig. 9.

Referring to Fig. 4 of thedrawings, the. thread It] constructed according to the preferred form of the invention is in the form generally of a longitudinally slitted tube of rubber, the edges H and 12 thereof being smooth and rounded so as not to present irregularities such as might render the thread vulnerable to rupture or which might promote chafing of the rubber. The least rounded portions of the edges, Ma and llb, are disposed at an inner sheltered position in the completed thread, as shown in Fig. 4, so that these portions occupy positions in. which they are protected from chafing by an enclosing structure which accordingly will contact only the'exterior, well-rounded portions of the thread.

It will be understood. that Fig. 4 is greatly enlarged for clarity of illustration,,the actual thread for most uses being of minute cross-section.

The generally tubular form ofthe thread is advantageous, especially whenthethread has wound upon it a fibrous strand wrapping, as owing to the laterally folded formation of the rubber that results from such wrapping, a number ofv longitudinally extending ridges or folds are presented against which the binding force of: the Wrapping is largely localized, accordingly with. greater resistance to slippage thanv if the binding force were evenly distributed along the helicalwrapping as would be the case if the rubber thread were purely cylindrical. At the. same time the improved thread is devoid of exposed sharp edges. such as are present on threads of rectangular form, and are subject to cutting or chafing. Also,

the improved thread is well adapted to twisting, if a twisted thread is desired.

The material of the thread is a dried andpreferably vulcanized deposit of a liquid dispersed rubber, preferably a natural or artificial. latex.

According to the preferred procedure for making the thread, an endless or long length of fine wire, preferably of circular or other curved surface form, is progressively coated entirely around its circumference with a deposit of therlatex, and, before the deposit has completely dried, it is stripped from the wire by progressive separation of the coating longitudinally thereof. The separation is effected preferably by progressively squeezing the rubber deposit between the wire and a: heated roller or other surface over' which the coated wire ispassed, the temperatureof such surface being maintained sufiiciently to soften the rubber to permit the wire. to pass through it without requiring a sharp edge on the wire, and to form smooth and rounded cleavage surfaces. Besides causing a local softening of the rubber, thereby facilitating the: separation, the presence of the heat causes vaporization of the water in the latex, this vapor serving advantageously to lubricate the: surfaces of. the deposit to facilitate removal of it from the wire and. to prevent its adhesion to the heated roll.

The squeezing and drying of the rubber at the heated surface alsoimparts a toughness to the thread locally at the zone of cleavage which facilitates the subsequent handling of the thread be fore: it is completely dried and vulcanized: without breaking or objectionably distorting it.

The operation of coating the wire may be carried out in any desired mannenwhether' by'electro-deposition, an extrusion process, a clipping procedure, with the aid of a chemical coagulant or with heat coagulationor any' other suitable procedure;

In the apparatus of Fig; 1', an endless round wire l3; guided by pulleys. M, It, and: suitably driven by one of them, passes vertically upward through a tank l of latex, the tank" being provided: at its-bottom with a gasket'seal I16? to" perrmitentrance ofthe wire without leakag'e- A supply container ll may be connected: with the tank I5 for supply and circulation of the latex. The deposition of the latex coating upon the wire may be effected in any suitable manner, for example, by the electro-deposition process, or by heating the wire to effect coagulation, which latter may be effected for example by electrical induction, or simply by the use of a highly -,concentrated or thickened dispersion.

The wire may be of steel or any other suitable material, and for corrosion resistance and avoidance of gas formation it may be plated with zinc or any other suitable material.

Above the coating tank IS, in a position to contact and bear against the rising coated wire l8 before the deposit has completely dried, there is mounted on a horizontal axis a roller l9 at the surface of which the.rubber thread I 0 is stripped from the wire as the latter passes over the roller and squeezes its way through the deposit against the surface of the roller as a backing, as shown most clearly in Figs. 2 and 3. The roller I9 is heated, as by means of an electric heating unit 20 mounted in the interior of the roller and supplied with current by means of a ring and brush device 2| associated with one end of the roller axle.

The roller is maintained at a temperature suff cient to soften the rubber locally for easy passage of the round wire through it, and in such softened condition the edge surfaces at the cleavage of the rubber are self healing as to irregularities which may be caused by the separation, resulting in the uniform, smooth rounded form of Fig. 4. The presence of the heat, moreover, causes some vaporization of the water in the latex coating which serves as a lubricant for the surface of the rubber coating, as above described.

The rubber thread is progressively separated from the wire and fed away upon a conveyor 22 disposed adjacent to the roller I9, the conveyor 22 being driven at a speed preferably fast enough to impart tension to the thread being drawn from the wire l8, which tension facilitates the separation. It has been found that the unvulcanized and not fully dried rubber is sufficiently strong to withstand considerable tension for this purpose. Besides facilitating the separation, the pulling of the thread at this stage of the procedure results in a condition in the final vulcanized thread of higher modulus, that is to say, -a condition in which a greater force is needed to stretch it, which is advantageous for most uses, as in the application to elastic garments. The thread is conducted through a series of containers and chambers for treatment, including, for example, a hot water washing container 23, a container 24 for coating the thread with a soap solution or other lubricant to render its surface non-tacky, a drying oven 25, and a vulcanizing chamber 26. From the latter the thread is fed to. a winding reel 21 for handling the finished product.

--"A rotating brush tact with the back face of the wire I3 these surfaces clean.

The apparatus of the embodiment of Figs. 5-8 is suited to the use of long lengths of wire rather than the endless wire of Fig. 1. A length 30of such wire is fed from a reel 3| vertically up ward through a coating tank 32 from which the coated wire 33 is passed through a drying chamber 34 to partially dry the coatingand thereby toughen it so that bycareful manipulation it may be handled without objectionable distortion.

28 may be provided in conof the roller l9 and the surin its return reach to keep The coated wire 33 is fed from the drying chamber 34 through a dusting chamber 35 to render its surface non-tacky, and it is then wound upon a reel 36.

This reel may then be transferred to another station (Fig. 6) for stripping the rubber from the wire, this being effected, as in the first described embodiment, by means of a heated roller 31 against which the coated wire 33 is brought and from which the separated rubber thread 38 is drawn. The wire 30 is rewound upon a reel 39 for recoating. The thread 38 is passed through a lubricating material 40, such as a soap solution, to render its surface non-tacky, and is then wound upon a reel 4|. While on the reel 4|, the thread may be washed by immersion in a bath of hot water 42 (Fig. 7), after which the reel may be transferred to another station (Fig. 8) where the rubber thread is unwound from the reel and is again lubricated, as by immersion in a soap solution 43, and is then fed through a curing oven 44. The vulcanized thread is then finally wound upon a reel 45.

In Figs. 9 and 10 is shown a modified separating roller construction by which two threads may be formed from a single coating on the wire, this being of advantage especially where exceedingly fine threads are desired. Instead of but one heated roller as in the above described embodiments, a pair of rollers 50, 5| are provided, rotating on parallel axes and with their surfaces spaced apart only enough to permit passage of the wire 52 between them with some pressure against the wire. In order to supply such pressure against the wire, one of the rollers may be spring-pressed toward the other roller as shown at 53, 53. Each roller may be electrically heated as previously-de-- scribed for the roller l9. The coated wire 54 is passed between the rollers as shown in, Figs. 9 and 10 and the coating is progressively separated at the two positions of contact of the wire with the rollers, resulting in the formation of two half-tubular threads of rubber 55, 56, each of which may be drawn off, treated and reeled, as in the previously described embodiments.

While the invention has been described with reference to a strip form of circular cross-section, wires or other strip forms of other crosssections may be used if desired. These and other variations may be made without departing from the scope of the invention as it is hereinafter claimed.

I claim:

1. Elastic thread comprising strip rubber the cross-section of which is a part cross-section of a tube of rounded concave inner surface and the outer marginal surfaces of the strip being rounded toward the interior of the tube. 2. Elastic thread comprising rubber in the form of a longitudinally slitted tube of round inner and outer surfaces and substantially uniform wall thicknessthroughout its cross-section, the outer marginal surfaces of the tube being rounded toward the interior of the tube.

3. Elastic thread comprising rubber in open, round tubular form presenting longitudinally extending rounded margins.

4. The method of making strip rubber which comprises coating a strip form of convexly curved outer surface with rubber, separating the coating longitudinally by squeezing it between the curved surface of the form and a blunt surface, and stripping the rubber coating from the form ina substantially unvulcanized condition.

5. The method of making strip rubber which comprises coating around wire with rubber, separating the coating longitudinally by passing the coated wire over and against a blunt roller surface, and removing the coating from the wire in a substantially unvulcanized condition.

6. The method of making strip rubber which comprises providing a coating of rubber upon a strip form of convexly curved outer surface by deposition from an aqueous dispersion of the rubber, and before the coating has completely dried, effecting separation of the coating longitudinally thereof along the curved surface of the form, and removing the rubber from the form.

'7. The method of making strip rubber which comprises coating a strip form with rubber, separating the coating longitudinally, the separation being effected by squeezing the rubber between the form and a heated surface, and removing the rubber from the form.

8. The method of making strip rubber which comprises providing a coating of rubber upon a form of curved surface by deposition from an aqueous dispersion of the rubber, and before the coating has completely dried effecting separation of the coating longitudinally thereof by squeezing the coating between the curved surface of the form and a heated surface, then removing the coating from the form and drying it.

9. A method as defined in claim 8 in which the rubber coating is removed from the form by drawing it therefrom under tension.

10. The method of making strip rubber which comprises coating a strip form with rubber, separating the coating along a plurality of lines extending longitudinally of the form at circumferentially spaced positions thereon, the separation being effected by squeezing the rubber coating between the form and a plurality of heated surfaces applied at said spaced positions on the form, removing the rubber from the form to provide a plurality of the strips.

11. Apparatus for making strip rubber, said apparatus comprising means for forming a tube of unvulcanized rubber, and means for effecting separation of the tube wall longitudinally thereof comprising means for determinately stretching the tube longitudinally.

12. Apparatus for making strip rubber, said apparatus comprising a strip form means for coating said form with rubber, a heated surface, and means for pressing the coated form against said surface.

13. Apparatus for making strip rubber, said apparatus comprising a strip form, means for coating said form with rubber, a heated surface, and means for feeding the coated form in pressure contact with said surface.

14. Apparatus for making strip rubber, said apparatus comprising a strip form, means for coating said form with rubber, a roller, means for heating the surface thereof, and means for feeding the coated form in pressure contact with the heated surface of said roller.

15. Apparatus for making strip rubber, said apparatus comprising a strip form, means for coating said form with rubber, a roller, means for heatand ing the surface thereof, means for feeding the coated form in pressure contact with the heated surface of said roller to separate the rubber coating longitudinally thereof, and means for drawing the separated coating from the form.

16. Apparatus as defined in claim 15 in which the strip form is endless and the feeding means is adapted to feed the form in a circuit through the coating means and past the heated roller.

17. Apparatus for making strip rubber, said apparatus comprising a strip form, means for coating said form with rubber, a pair of rollers, means for heating the surfaces thereof, means for drawing the coated form past said rollers and pressing the coated form against the heated surfaces at circumferentially spaced positions on the form to separate the coating longitudinally thereof into a plurality of threads.

18. Apparatus as defined in claim 17 in which the rollers are arranged to rotate on parallel axes and to squeeze the rubber coating between them and the form at diametrically opposite positions on the latter.

19. Apparatus for making rubber thread, said apparatus comprising a strip form of convexly curved outer surface, means for coating the form with rubber, a blunt surfaced roller, and means for passing the coated form over and against the surface of said roller to effect separation of the coating.

20. The method of making rubber thread which comprises coating a strip form with rubber, separating the coating longitudinally thereof and removing it while determinately stretching it, the rubber being still unvulcanized.

21. Apparatus for making rubber thread, said apparatus comprising a strip form, means for coating said form with unvulcanized rubber, means for effecting separation of the coating longitudinally thereof, and means for removing the coating from the form comprising means for determinately stretching the rubber while it is still unvulcanized.

22. The method of making strip rubber which comprises coating a round wire with a rubber composition by passing the wire through a liquid dispersion of rubber, longitudinally severing a wall of the coating along a single line of severance, and stripping the coating from the wire.

23. The method of making strip rubber which i comprises coating a round wire with a rubber composition by passing the wire through a liquid dispersion of rubber, longitudinally severing a wall of the coating along a single line of severance, and stripping the coating from the wire while it is still in a substantially unvulcanized condition.

24. Apparatus for making strip rubber, said apparatus comprising a round wire, means for applying a coating of rubber thereto from a liquid dispersion of rubber, means for severing the coating while it is on the wire, along a single, longitudinal line of severance, and means for pulling the severed coating from the wire.

CHARLES W. LEGUILLON. 

